Fuel Storage: How Much Gas to Keep and How to Keep It Safe
Figure out how much fuel your car and generator really need, store it in approved cans outside your living space, and rotate it before it goes stale.
⚠ Where gasoline is allowed to live
Store gasoline only in approved fuel containers, outside your living space, and away from anything that can light it.[1][2][4]
- Keep it in a detached shed or other protected spot outside the house, never inside the home and never in an attached garage that shares air with your living space.[1][3]
- Keep it away from fuel-burning appliances like a gas water heater, furnace, or anything with a pilot light. Gas vapor is heavier than air and can creep along the floor to a flame.[1][4][8]
- Keep it out of direct sun and away from heat.[4]
- Local fire codes can limit how much fuel you keep and where. Call your fire department's non-emergency line and ask.[1]
Storms can spike demand and disrupt fuel deliveries,[6] so a small, well-kept fuel supply lets you run a generator or leave town on your own schedule. The goal isn't a big stockpile. It's the right amount for your car and your generator, stored safely and kept fresh.
How much do I need?
Generator fuel = gallons per hour × hours per day × days. Example: a generator that burns 0.67 gallons an hour[8], run 8 hours a day for 3 days, needs about 0.67 × 8 × 3 = 16 gallons. Run it nonstop for 48 hours and it's about 32 gallons.[8] Swap in your own manual's number, then check your local limit on how much you can store.[1]
Work out how much you actually need
Start with your vehicles, then your generator.
- Vehicles: the simplest fuel storage is your gas tank. Keep it at least half full during storm season.[12]
- Generator: look up how many gallons per hour it burns in its owner's manual, then multiply by the hours you plan to run it. One county consumer office uses about 0.67 gallons per hour as a typical figure, which works out to roughly 32 gallons for 48 hours of nonstop running.[8]
- Stretch it: many people run the generator only a few hours a day to save fuel.[8]
Your own manual's number beats any average. Use it.
Use containers made for the job
- Use cans that carry an approval label. Look for a UL or ASTM stamp; gasoline cans are usually red.[5][6]
- Other colors mean other fuels: blue is usually kerosene and yellow is usually diesel. Don't mix them up.[6]
- Never use milk jugs, glass, or open-top containers.[4][6]
- Replace cans that are rusted, dented, leaking, or missing parts.[5]
- Fill cans no more than 95% full so the fuel has room to expand when it warms up.[4][5]
- Set the can on the ground to fill it, never in a truck bed or trunk.[4][6]
Keep it fresh: stabilizer, labels, and rotation
Gasoline goes stale, and stale gas is hard to get rid of safely.[4] A fuel stabilizer (an additive that helps gas stay usable longer) is recommended for stored generator fuel.[6] One county office suggests using it whenever a generator will sit unused for 30 days or longer.[8]
- Add stabilizer when you fill the can, following the dose on the bottle.
- Write the fill date on every can with a paint marker or tape label.
- Rotate roughly every six months. Florida's agriculture department says properly stored fuel can be kept through a hurricane season and then poured into your vehicle if you never needed it.[6] The Atlantic hurricane season runs June 1 to November 30, about six months.[7]
- Never dump old gas on the ground, down a drain, or in the trash. Use it in a car or take it to a household hazardous waste drop-off.[4]
Ethanol vs. non-ethanol gas for small engines
Most regular gas is E10, which means up to 10% ethanol (an alcohol made from plants). It's approved for any normal gas car.[10]
- E15 is different. It's not allowed in lawn mowers, chain saws, boats, snowmobiles, or motorcycles.[9] Check the pump label before filling a can for small engines.
- Why ethanol matters in storage: ethanol blends soak up much more water than plain gas. At 60°F, E10 can hold about 0.5% water before the water and ethanol drop out as a separate layer at the bottom.[11]
- That layer can strip the oil that lubricates two-stroke engines (the kind where you mix oil into the gas) and can make other engines run too lean, which can damage them.[11]
- Most of that water gets in as liquid, through open vents or rain, so tight caps matter.[11]
That's why some people choose ethanol-free gas for small engines that sit a long time. Follow what your engine's manual says.
Checklist
Mistakes to avoid
- Storing gas cans inside the house or in an attached garage
- Keeping fuel next to a gas water heater or anything with a pilot light
- Filling a can while it sits in a truck bed or trunk
- Putting E15 in a lawn mower, chain saw, or other small engine
- Forgetting to date cans, so nobody knows how old the gas is
- Pouring old gas on the ground or down a drain
Do this this weekend
Find your generator manual (or look it up online by model number), write its gallons-per-hour on a piece of tape, and stick it on the generator. Then label every gas can you own with today's date and check each one for rust, dents, or a missing cap.[5]
Gear that helps
Affiliate links: we may earn a commission, at no cost to you. We list items for why they matter, never by price or ratings. Disclosure
- Fuel cans5-gallon approved gasoline canApproved cans are built to vent and seal safely; label each with the fill date so you rotate it.Check it (opens retailer site)
- Fuel cans5-gallon diesel can (yellow)Color-coded cans keep diesel and gasoline from getting mixed up.Check it (opens retailer site)
- Fuel stabilizerFuel stabilizerSlows the breakdown of stored gasoline so it still starts your generator months later.Check it (opens retailer site)
- Fuel stabilizerEthanol fuel treatment for small enginesHelps protect small engines from ethanol-related water problems in stored fuel.Check it (opens retailer site)
- GeneratorsInverter generator (with CO shutoff)Runs a fridge, lights and phones in an outage. Pick one with automatic carbon monoxide shutoff, and only ever run it outdoors, far from the house.Check it (opens retailer site)
- GeneratorsHeavy-duty outdoor generator extension cordA properly rated outdoor cord safely carries power from a generator that's running well away from the house.Check it (opens retailer site)
Sources
- Generator Safety Red Cross
- Generator Safety Tip Sheet NFPA
- Basement and Garage Fire Safety US Fire Administration
- Gasoline Safety Fact Sheet Maryland Department of the Environment
- Fire Prevention 52: Gas Cans National Park Service
- Storm Preparation: Have a Fuel Plan Florida Department of Agriculture and Consumer Services
- Tropical Cyclone Climatology NOAA National Hurricane Center
- Hurricane Season: Getting a Gas Generator Palm Beach County Consumer Affairs
- E15 Fuel Registration: About E15 Fuel EPA
- Ethanol Blends DOE Alternative Fuels Data Center
- Memorandum: Water Phase Separation in Oxygenated Gasoline EPA
- Power Outage Safety Red Cross
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